Abstract : Internal conversion of low-energy nuclear transitions occurs with a high probability in heavy nuclei. After the emission of the conversion electron, a cascade of X-rays, Auger or Coster–Krönig electrons takes place. In $\alpha$-decay experiments in which the nuclei of interest are implanted into a silicon detector, these atomic processes contribute to the detected energy. To understand the distortions of $\alpha$-particle energy spectra, knowledge of the various atomic yields is required. Using state-of-the-art calculations, new atomic yields are computed in $_99$Es and compared to those available in the literature. Detailed simulations of the $^{251}_{101}$Md $\alpha$ decay are performed and compared to experimental data. Possible ways to discriminate between the available atomic yields are also discussed.